Field of the Invention
The present invention generally relates to a cooling device used in a printer, a facsimile machine, a copy machine or the like, and an image forming apparatus including the cooling device.
Discussion of the Background Art
One type of image forming apparatus is known in which an electrophotographic technology is used for forming a toner image on a recording material.
Japanese Patent No. 4114864 discloses a cooling device including a pair of transport belts to transfer a sheet, and a cooling surface of a cooling member contacts an internal surface of the transport belts. When the sheet, which is conveyed to the transport belts, passes an area facing the cooling member, the sheet is cooled as heat is removed from the sheet via the transport belt. This process also reduces adherence of a toner that is softened by a fixing device to the transport belts or a transport roller.
In addition, cooling the sheet by a cooling device, can reduce passing the softened toner (so-called “blocking phenomenon”) between stacked sheets at the eject tray.
For fully cooling thick paper, which has a heat capacity that is large and does not cool easily according to high productivity of the image forming apparatus, the cooling device requires a plurality of cooling members. Therefore, the cooling device is expensive. In particular, for users to use only thin paper or standard thickness paper, which has a thermal capacity that is small and is easy to cool, the cooling device including the plurality of cooling devices, as mentioned above, is unnecessary. In addition, the user contributes to a waste of cost. Therefore, when a user who does not print the thick paper, uses an image forming apparatus which has a minimal number of cooling members rather than that of the image forming apparatus for the thick paper, it is possible to prevent unnecessary high costs.
However, when a user, who prints only thin paper or standard thickness paper, needs to print a thick paper, the user needs to buy the image forming apparatus including the cooling device for thick paper. Therefore, the user pays the cost of the other image forming apparatus.